In most hospital critical care settings, bedside patient monitors are routinely employed for real time monitoring and display of the patient's electrocardiogram (ECG) and/or other clinically important variables.
The types of bedside monitors employed range from simple, relatively portable, single channel ECG monitors to larger, more complex multi-channel monitors. Typically, the simple, one channel ECG monitors incorporate a small screen for displaying the patient's ECG. The typical multi-channel bedside monitor consist of a larger, wall mounted unit having one or more display screens whereupon multiple variables, tracings or physiological waveforms (ECG, arterial pressure, central venous pressure, pulmonary artery pressure, respiratory flow, etc.) may be simultaneously displayed.
Most, if not all commercially available bedside monitors incorporate signal output jacks for each channel displayed. Ancillary devices such as strip chart recorders may then be connected to these signal output jacks by way of connecting cables, wires, or other interconnection means.
In normal operation, the bedside ECG monitor receives input (i.e. sensed voltage changes from various points on the patient's body) from a plurality of skin-contacting electrodes positioned at selected anatomical points on the patient's body. Adhesive patch type electrodes are most frequently employed because they are comfortable for the patient to wear and tend to remain in their desired positions without need for attachment of retainer bands, straps, or other attachment means. Pectoral lead electrodes are placed in contact with the arms, or shoulders of the patient, while pelvic lead electrodes are placed in contact with the legs or lower quadrants of the patient's abdomen. Also, if it is desired to effect monitoring of ECG leads V1 through V6, an additional chest electrode must be provided for attachment to prescribed points on the patient's chest. Thus, as many as five separate electrodes may remain attached to the patient during routine bedside ECG monitoring.
A "patient cable" is employed to carry the sensed ECG voltage changes from the skin contacting ECG electrodes to the bedside ECG monitor. Typically, such "patient cable" comprises a length of electrically conductive cable. The proximal end of the cable is provided with a plug or connector for attachment to the bedside monitor. The distal end of the cable is furcated into as many as five (5) separate wires or cables, each such furcated segment being independently connectable to skin-contacting ECG electrodes (e.g. two (2) pectoral electrodes, two (2) pelvic electrodes, and/or one (1) chest electrode).
The primary purpose for bedside ECG monitoring in critical care facilities is to effectuate rapid detection and treatment of cardiac arrhythmias and/or cardiac arrest. Upon detection of a serious or life threatening cardiac arrhythmia, it is desirable to administer anti-arrhythmic treatment as rapidly as possible. Some cardiac arrhythmias are preferrably treated by administration of anti-arrhythmic drugs while other cardiac arrhythmias are preferrably treated by immediate electroshock (i.e. DC cardioversion).
In treating arrhythmias for which emergency cardioversion is the treatment of choice, it is common practice to deploy a portable defibrillator/ECG machine to the bedside. Such portable defibrillator/ECG machine incorporates a small ECG monitor in combination with an electroshock machine having paddle type electrodes. The paddle type electrodes are positionable in contact with the patient's chest so as to administer a timed electroshock to the arrhythmic heart. The defibrillator/ECG machine incorporates internal synchronizing circuitry whereby the delivery of the electroshock is timed in accordance with the patient's ECG activity. Such timed delivery of the electroshock is particularly important in certain arrhythmias (e.g. ventricular tachycardia) wherein it is desirable to administer the electroshock at a specific point during the cardiac contraction cycle. An ill timed electroshock of the heart during ventricular tachycardia may cause the heart to regress to a state of fibrillation while a properly timed electroshock is likely to effect successful cardioversion of the ventricular tachycardia to a relatively normal sinus rhythm.
Although DC cardioversion offers an effective means for treating certain life threatening cardiac arrhythmias, it must be appreciated that the speed with which such treatment is delivered may be of great importance. For example, critically ill patients who experience unstable ventricular tachycardia are likely to further degenerate into ventricular fibrillation within a short time (e.g. 2-5 minutes) if DC cardioversion is not undertaken. Once the heart has lapsed into fibrillation, the chances for successful recussitation of the patient are substantially lessened. Thus it is highly desirable to electroshock the heart as rapidly as possible when ventricular tachycardia is detected.
The time required to deliver the electroshock is largely devoted to deployment, set up and preparation of the defibrillator/ECG machine. In setting up the defibrillator/ECG machine it is generally necessary to attach a second patient cable and/or a second set of skin contacting electrodes to effect input of the ECG signal to the defibrillator/ECG machine.
To wit: upon detection of a cardiac arrhythmia treatable by DC cardioversion, it is generally necessary for the critical care staff personnel to rapidly apply at least three and sometimes as many as five additional ECG electrodes to the patient's body and to subsequently deploy a secondary patient cable to interconnect the newly applied ECG electrodes to the defibrillator/ECG machine. The attachment of additional electrodes, and the deployment of a second "patient cable" is time consuming and generally redundant in view of the fact that patient's who are connected to a bedside ECG monitor are already outfitted with a full set of properly positioned ECG electrodes and connected to the bedside monitor by way of a standard patient cable. While it would seem a simple matter to merely extract the proximal end of the patient cable from the bedside monitor and, alternately, insert it into the input jack of the defibrillator/ECG machine, such is oftentimes nonfeasible because the size and/or configuration of the patient/cable connector is incompatable with the input jack of the defibrillator/ECG machine.
In light of the compelling need for rapid deployment and effectuation of emergency cardioversion, there exists a need in the art for a means for rapidly connecting a portable defibrillator/ECG machine to the output jack of a functional bedside ECG monitor so as to eliminate the need for attachment of additional ECG electrodes and/or deployment of a second "patient cable".